1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Generic infrastructure for lifetime debugging of objects.
4 *
5 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
6 */
7
8#define pr_fmt(fmt) "ODEBUG: " fmt
9
10#include <linux/debugobjects.h>
11#include <linux/interrupt.h>
12#include <linux/sched.h>
13#include <linux/sched/task_stack.h>
14#include <linux/seq_file.h>
15#include <linux/debugfs.h>
16#include <linux/slab.h>
17#include <linux/hash.h>
18#include <linux/kmemleak.h>
19#include <linux/cpu.h>
20
21#define ODEBUG_HASH_BITS 14
22#define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS)
23
24#define ODEBUG_POOL_SIZE 1024
25#define ODEBUG_POOL_MIN_LEVEL 256
26#define ODEBUG_POOL_PERCPU_SIZE 64
27#define ODEBUG_BATCH_SIZE 16
28
29#define ODEBUG_CHUNK_SHIFT PAGE_SHIFT
30#define ODEBUG_CHUNK_SIZE (1 << ODEBUG_CHUNK_SHIFT)
31#define ODEBUG_CHUNK_MASK (~(ODEBUG_CHUNK_SIZE - 1))
32
33/*
34 * We limit the freeing of debug objects via workqueue at a maximum
35 * frequency of 10Hz and about 1024 objects for each freeing operation.
36 * So it is freeing at most 10k debug objects per second.
37 */
38#define ODEBUG_FREE_WORK_MAX 1024
39#define ODEBUG_FREE_WORK_DELAY DIV_ROUND_UP(HZ, 10)
40
41struct debug_bucket {
42 struct hlist_head list;
43 raw_spinlock_t lock;
44};
45
46/*
47 * Debug object percpu free list
48 * Access is protected by disabling irq
49 */
50struct debug_percpu_free {
51 struct hlist_head free_objs;
52 int obj_free;
53};
54
55static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
56
57static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];
58
59static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
60
61static DEFINE_RAW_SPINLOCK(pool_lock);
62
63static HLIST_HEAD(obj_pool);
64static HLIST_HEAD(obj_to_free);
65
66/*
67 * Because of the presence of percpu free pools, obj_pool_free will
68 * under-count those in the percpu free pools. Similarly, obj_pool_used
69 * will over-count those in the percpu free pools. Adjustments will be
70 * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
71 * can be off.
72 */
73static int obj_pool_min_free = ODEBUG_POOL_SIZE;
74static int obj_pool_free = ODEBUG_POOL_SIZE;
75static int obj_pool_used;
76static int obj_pool_max_used;
77static bool obj_freeing;
78/* The number of objs on the global free list */
79static int obj_nr_tofree;
80
81static int debug_objects_maxchain __read_mostly;
82static int __maybe_unused debug_objects_maxchecked __read_mostly;
83static int debug_objects_fixups __read_mostly;
84static int debug_objects_warnings __read_mostly;
85static int debug_objects_enabled __read_mostly
86 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
87static int debug_objects_pool_size __read_mostly
88 = ODEBUG_POOL_SIZE;
89static int debug_objects_pool_min_level __read_mostly
90 = ODEBUG_POOL_MIN_LEVEL;
91static const struct debug_obj_descr *descr_test __read_mostly;
92static struct kmem_cache *obj_cache __ro_after_init;
93
94/*
95 * Track numbers of kmem_cache_alloc()/free() calls done.
96 */
97static int debug_objects_allocated;
98static int debug_objects_freed;
99
100static void free_obj_work(struct work_struct *work);
101static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
102
103static int __init enable_object_debug(char *str)
104{
105 debug_objects_enabled = 1;
106 return 0;
107}
108
109static int __init disable_object_debug(char *str)
110{
111 debug_objects_enabled = 0;
112 return 0;
113}
114
115early_param("debug_objects", enable_object_debug);
116early_param("no_debug_objects", disable_object_debug);
117
118static const char *obj_states[ODEBUG_STATE_MAX] = {
119 [ODEBUG_STATE_NONE] = "none",
120 [ODEBUG_STATE_INIT] = "initialized",
121 [ODEBUG_STATE_INACTIVE] = "inactive",
122 [ODEBUG_STATE_ACTIVE] = "active",
123 [ODEBUG_STATE_DESTROYED] = "destroyed",
124 [ODEBUG_STATE_NOTAVAILABLE] = "not available",
125};
126
127static void fill_pool(void)
128{
129 gfp_t gfp = __GFP_HIGH | __GFP_NOWARN;
130 struct debug_obj *obj;
131 unsigned long flags;
132
133 if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
134 return;
135
136 /*
137 * Reuse objs from the global free list; they will be reinitialized
138 * when allocating.
139 *
140 * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
141 * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
142 * sections.
143 */
144 while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
145 raw_spin_lock_irqsave(&pool_lock, flags);
146 /*
147 * Recheck with the lock held as the worker thread might have
148 * won the race and freed the global free list already.
149 */
150 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
151 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
152 hlist_del(n: &obj->node);
153 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
154 hlist_add_head(n: &obj->node, h: &obj_pool);
155 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
156 }
157 raw_spin_unlock_irqrestore(&pool_lock, flags);
158 }
159
160 if (unlikely(!obj_cache))
161 return;
162
163 while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
164 struct debug_obj *new[ODEBUG_BATCH_SIZE];
165 int cnt;
166
167 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
168 new[cnt] = kmem_cache_zalloc(k: obj_cache, flags: gfp);
169 if (!new[cnt])
170 break;
171 }
172 if (!cnt)
173 return;
174
175 raw_spin_lock_irqsave(&pool_lock, flags);
176 while (cnt) {
177 hlist_add_head(n: &new[--cnt]->node, h: &obj_pool);
178 debug_objects_allocated++;
179 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
180 }
181 raw_spin_unlock_irqrestore(&pool_lock, flags);
182 }
183}
184
185/*
186 * Lookup an object in the hash bucket.
187 */
188static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
189{
190 struct debug_obj *obj;
191 int cnt = 0;
192
193 hlist_for_each_entry(obj, &b->list, node) {
194 cnt++;
195 if (obj->object == addr)
196 return obj;
197 }
198 if (cnt > debug_objects_maxchain)
199 debug_objects_maxchain = cnt;
200
201 return NULL;
202}
203
204/*
205 * Allocate a new object from the hlist
206 */
207static struct debug_obj *__alloc_object(struct hlist_head *list)
208{
209 struct debug_obj *obj = NULL;
210
211 if (list->first) {
212 obj = hlist_entry(list->first, typeof(*obj), node);
213 hlist_del(n: &obj->node);
214 }
215
216 return obj;
217}
218
219static struct debug_obj *
220alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
221{
222 struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
223 struct debug_obj *obj;
224
225 if (likely(obj_cache)) {
226 obj = __alloc_object(list: &percpu_pool->free_objs);
227 if (obj) {
228 percpu_pool->obj_free--;
229 goto init_obj;
230 }
231 }
232
233 raw_spin_lock(&pool_lock);
234 obj = __alloc_object(list: &obj_pool);
235 if (obj) {
236 obj_pool_used++;
237 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
238
239 /*
240 * Looking ahead, allocate one batch of debug objects and
241 * put them into the percpu free pool.
242 */
243 if (likely(obj_cache)) {
244 int i;
245
246 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
247 struct debug_obj *obj2;
248
249 obj2 = __alloc_object(list: &obj_pool);
250 if (!obj2)
251 break;
252 hlist_add_head(n: &obj2->node,
253 h: &percpu_pool->free_objs);
254 percpu_pool->obj_free++;
255 obj_pool_used++;
256 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
257 }
258 }
259
260 if (obj_pool_used > obj_pool_max_used)
261 obj_pool_max_used = obj_pool_used;
262
263 if (obj_pool_free < obj_pool_min_free)
264 obj_pool_min_free = obj_pool_free;
265 }
266 raw_spin_unlock(&pool_lock);
267
268init_obj:
269 if (obj) {
270 obj->object = addr;
271 obj->descr = descr;
272 obj->state = ODEBUG_STATE_NONE;
273 obj->astate = 0;
274 hlist_add_head(n: &obj->node, h: &b->list);
275 }
276 return obj;
277}
278
279/*
280 * workqueue function to free objects.
281 *
282 * To reduce contention on the global pool_lock, the actual freeing of
283 * debug objects will be delayed if the pool_lock is busy.
284 */
285static void free_obj_work(struct work_struct *work)
286{
287 struct hlist_node *tmp;
288 struct debug_obj *obj;
289 unsigned long flags;
290 HLIST_HEAD(tofree);
291
292 WRITE_ONCE(obj_freeing, false);
293 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
294 return;
295
296 if (obj_pool_free >= debug_objects_pool_size)
297 goto free_objs;
298
299 /*
300 * The objs on the pool list might be allocated before the work is
301 * run, so recheck if pool list it full or not, if not fill pool
302 * list from the global free list. As it is likely that a workload
303 * may be gearing up to use more and more objects, don't free any
304 * of them until the next round.
305 */
306 while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
307 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
308 hlist_del(n: &obj->node);
309 hlist_add_head(n: &obj->node, h: &obj_pool);
310 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
311 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
312 }
313 raw_spin_unlock_irqrestore(&pool_lock, flags);
314 return;
315
316free_objs:
317 /*
318 * Pool list is already full and there are still objs on the free
319 * list. Move remaining free objs to a temporary list to free the
320 * memory outside the pool_lock held region.
321 */
322 if (obj_nr_tofree) {
323 hlist_move_list(old: &obj_to_free, new: &tofree);
324 debug_objects_freed += obj_nr_tofree;
325 WRITE_ONCE(obj_nr_tofree, 0);
326 }
327 raw_spin_unlock_irqrestore(&pool_lock, flags);
328
329 hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
330 hlist_del(n: &obj->node);
331 kmem_cache_free(s: obj_cache, objp: obj);
332 }
333}
334
335static void __free_object(struct debug_obj *obj)
336{
337 struct debug_obj *objs[ODEBUG_BATCH_SIZE];
338 struct debug_percpu_free *percpu_pool;
339 int lookahead_count = 0;
340 unsigned long flags;
341 bool work;
342
343 local_irq_save(flags);
344 if (!obj_cache)
345 goto free_to_obj_pool;
346
347 /*
348 * Try to free it into the percpu pool first.
349 */
350 percpu_pool = this_cpu_ptr(&percpu_obj_pool);
351 if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
352 hlist_add_head(n: &obj->node, h: &percpu_pool->free_objs);
353 percpu_pool->obj_free++;
354 local_irq_restore(flags);
355 return;
356 }
357
358 /*
359 * As the percpu pool is full, look ahead and pull out a batch
360 * of objects from the percpu pool and free them as well.
361 */
362 for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
363 objs[lookahead_count] = __alloc_object(list: &percpu_pool->free_objs);
364 if (!objs[lookahead_count])
365 break;
366 percpu_pool->obj_free--;
367 }
368
369free_to_obj_pool:
370 raw_spin_lock(&pool_lock);
371 work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
372 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
373 obj_pool_used--;
374
375 if (work) {
376 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
377 hlist_add_head(n: &obj->node, h: &obj_to_free);
378 if (lookahead_count) {
379 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
380 obj_pool_used -= lookahead_count;
381 while (lookahead_count) {
382 hlist_add_head(n: &objs[--lookahead_count]->node,
383 h: &obj_to_free);
384 }
385 }
386
387 if ((obj_pool_free > debug_objects_pool_size) &&
388 (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
389 int i;
390
391 /*
392 * Free one more batch of objects from obj_pool.
393 */
394 for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
395 obj = __alloc_object(list: &obj_pool);
396 hlist_add_head(n: &obj->node, h: &obj_to_free);
397 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
398 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
399 }
400 }
401 } else {
402 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
403 hlist_add_head(n: &obj->node, h: &obj_pool);
404 if (lookahead_count) {
405 WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
406 obj_pool_used -= lookahead_count;
407 while (lookahead_count) {
408 hlist_add_head(n: &objs[--lookahead_count]->node,
409 h: &obj_pool);
410 }
411 }
412 }
413 raw_spin_unlock(&pool_lock);
414 local_irq_restore(flags);
415}
416
417/*
418 * Put the object back into the pool and schedule work to free objects
419 * if necessary.
420 */
421static void free_object(struct debug_obj *obj)
422{
423 __free_object(obj);
424 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
425 WRITE_ONCE(obj_freeing, true);
426 schedule_delayed_work(dwork: &debug_obj_work, ODEBUG_FREE_WORK_DELAY);
427 }
428}
429
430#ifdef CONFIG_HOTPLUG_CPU
431static int object_cpu_offline(unsigned int cpu)
432{
433 struct debug_percpu_free *percpu_pool;
434 struct hlist_node *tmp;
435 struct debug_obj *obj;
436 unsigned long flags;
437
438 /* Remote access is safe as the CPU is dead already */
439 percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
440 hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
441 hlist_del(n: &obj->node);
442 kmem_cache_free(s: obj_cache, objp: obj);
443 }
444
445 raw_spin_lock_irqsave(&pool_lock, flags);
446 obj_pool_used -= percpu_pool->obj_free;
447 debug_objects_freed += percpu_pool->obj_free;
448 raw_spin_unlock_irqrestore(&pool_lock, flags);
449
450 percpu_pool->obj_free = 0;
451
452 return 0;
453}
454#endif
455
456/*
457 * We run out of memory. That means we probably have tons of objects
458 * allocated.
459 */
460static void debug_objects_oom(void)
461{
462 struct debug_bucket *db = obj_hash;
463 struct hlist_node *tmp;
464 HLIST_HEAD(freelist);
465 struct debug_obj *obj;
466 unsigned long flags;
467 int i;
468
469 pr_warn("Out of memory. ODEBUG disabled\n");
470
471 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
472 raw_spin_lock_irqsave(&db->lock, flags);
473 hlist_move_list(old: &db->list, new: &freelist);
474 raw_spin_unlock_irqrestore(&db->lock, flags);
475
476 /* Now free them */
477 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
478 hlist_del(n: &obj->node);
479 free_object(obj);
480 }
481 }
482}
483
484/*
485 * We use the pfn of the address for the hash. That way we can check
486 * for freed objects simply by checking the affected bucket.
487 */
488static struct debug_bucket *get_bucket(unsigned long addr)
489{
490 unsigned long hash;
491
492 hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
493 return &obj_hash[hash];
494}
495
496static void debug_print_object(struct debug_obj *obj, char *msg)
497{
498 const struct debug_obj_descr *descr = obj->descr;
499 static int limit;
500
501 /*
502 * Don't report if lookup_object_or_alloc() by the current thread
503 * failed because lookup_object_or_alloc()/debug_objects_oom() by a
504 * concurrent thread turned off debug_objects_enabled and cleared
505 * the hash buckets.
506 */
507 if (!debug_objects_enabled)
508 return;
509
510 if (limit < 5 && descr != descr_test) {
511 void *hint = descr->debug_hint ?
512 descr->debug_hint(obj->object) : NULL;
513 limit++;
514 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
515 "object: %p object type: %s hint: %pS\n",
516 msg, obj_states[obj->state], obj->astate,
517 obj->object, descr->name, hint);
518 }
519 debug_objects_warnings++;
520}
521
522/*
523 * Try to repair the damage, so we have a better chance to get useful
524 * debug output.
525 */
526static bool
527debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
528 void * addr, enum debug_obj_state state)
529{
530 if (fixup && fixup(addr, state)) {
531 debug_objects_fixups++;
532 return true;
533 }
534 return false;
535}
536
537static void debug_object_is_on_stack(void *addr, int onstack)
538{
539 int is_on_stack;
540 static int limit;
541
542 if (limit > 4)
543 return;
544
545 is_on_stack = object_is_on_stack(obj: addr);
546 if (is_on_stack == onstack)
547 return;
548
549 limit++;
550 if (is_on_stack)
551 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
552 task_stack_page(current));
553 else
554 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
555 task_stack_page(current));
556
557 WARN_ON(1);
558}
559
560static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
561 const struct debug_obj_descr *descr,
562 bool onstack, bool alloc_ifstatic)
563{
564 struct debug_obj *obj = lookup_object(addr, b);
565 enum debug_obj_state state = ODEBUG_STATE_NONE;
566
567 if (likely(obj))
568 return obj;
569
570 /*
571 * debug_object_init() unconditionally allocates untracked
572 * objects. It does not matter whether it is a static object or
573 * not.
574 *
575 * debug_object_assert_init() and debug_object_activate() allow
576 * allocation only if the descriptor callback confirms that the
577 * object is static and considered initialized. For non-static
578 * objects the allocation needs to be done from the fixup callback.
579 */
580 if (unlikely(alloc_ifstatic)) {
581 if (!descr->is_static_object || !descr->is_static_object(addr))
582 return ERR_PTR(error: -ENOENT);
583 /* Statically allocated objects are considered initialized */
584 state = ODEBUG_STATE_INIT;
585 }
586
587 obj = alloc_object(addr, b, descr);
588 if (likely(obj)) {
589 obj->state = state;
590 debug_object_is_on_stack(addr, onstack);
591 return obj;
592 }
593
594 /* Out of memory. Do the cleanup outside of the locked region */
595 debug_objects_enabled = 0;
596 return NULL;
597}
598
599static void debug_objects_fill_pool(void)
600{
601 /*
602 * On RT enabled kernels the pool refill must happen in preemptible
603 * context -- for !RT kernels we rely on the fact that spinlock_t and
604 * raw_spinlock_t are basically the same type and this lock-type
605 * inversion works just fine.
606 */
607 if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
608 /*
609 * Annotate away the spinlock_t inside raw_spinlock_t warning
610 * by temporarily raising the wait-type to WAIT_SLEEP, matching
611 * the preemptible() condition above.
612 */
613 static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
614 lock_map_acquire_try(&fill_pool_map);
615 fill_pool();
616 lock_map_release(&fill_pool_map);
617 }
618}
619
620static void
621__debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
622{
623 struct debug_obj *obj, o;
624 struct debug_bucket *db;
625 unsigned long flags;
626
627 debug_objects_fill_pool();
628
629 db = get_bucket(addr: (unsigned long) addr);
630
631 raw_spin_lock_irqsave(&db->lock, flags);
632
633 obj = lookup_object_or_alloc(addr, b: db, descr, onstack, alloc_ifstatic: false);
634 if (unlikely(!obj)) {
635 raw_spin_unlock_irqrestore(&db->lock, flags);
636 debug_objects_oom();
637 return;
638 }
639
640 switch (obj->state) {
641 case ODEBUG_STATE_NONE:
642 case ODEBUG_STATE_INIT:
643 case ODEBUG_STATE_INACTIVE:
644 obj->state = ODEBUG_STATE_INIT;
645 raw_spin_unlock_irqrestore(&db->lock, flags);
646 return;
647 default:
648 break;
649 }
650
651 o = *obj;
652 raw_spin_unlock_irqrestore(&db->lock, flags);
653 debug_print_object(obj: &o, msg: "init");
654
655 if (o.state == ODEBUG_STATE_ACTIVE)
656 debug_object_fixup(fixup: descr->fixup_init, addr, state: o.state);
657}
658
659/**
660 * debug_object_init - debug checks when an object is initialized
661 * @addr: address of the object
662 * @descr: pointer to an object specific debug description structure
663 */
664void debug_object_init(void *addr, const struct debug_obj_descr *descr)
665{
666 if (!debug_objects_enabled)
667 return;
668
669 __debug_object_init(addr, descr, onstack: 0);
670}
671EXPORT_SYMBOL_GPL(debug_object_init);
672
673/**
674 * debug_object_init_on_stack - debug checks when an object on stack is
675 * initialized
676 * @addr: address of the object
677 * @descr: pointer to an object specific debug description structure
678 */
679void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
680{
681 if (!debug_objects_enabled)
682 return;
683
684 __debug_object_init(addr, descr, onstack: 1);
685}
686EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
687
688/**
689 * debug_object_activate - debug checks when an object is activated
690 * @addr: address of the object
691 * @descr: pointer to an object specific debug description structure
692 * Returns 0 for success, -EINVAL for check failed.
693 */
694int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
695{
696 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
697 struct debug_bucket *db;
698 struct debug_obj *obj;
699 unsigned long flags;
700
701 if (!debug_objects_enabled)
702 return 0;
703
704 debug_objects_fill_pool();
705
706 db = get_bucket(addr: (unsigned long) addr);
707
708 raw_spin_lock_irqsave(&db->lock, flags);
709
710 obj = lookup_object_or_alloc(addr, b: db, descr, onstack: false, alloc_ifstatic: true);
711 if (unlikely(!obj)) {
712 raw_spin_unlock_irqrestore(&db->lock, flags);
713 debug_objects_oom();
714 return 0;
715 } else if (likely(!IS_ERR(obj))) {
716 switch (obj->state) {
717 case ODEBUG_STATE_ACTIVE:
718 case ODEBUG_STATE_DESTROYED:
719 o = *obj;
720 break;
721 case ODEBUG_STATE_INIT:
722 case ODEBUG_STATE_INACTIVE:
723 obj->state = ODEBUG_STATE_ACTIVE;
724 fallthrough;
725 default:
726 raw_spin_unlock_irqrestore(&db->lock, flags);
727 return 0;
728 }
729 }
730
731 raw_spin_unlock_irqrestore(&db->lock, flags);
732 debug_print_object(obj: &o, msg: "activate");
733
734 switch (o.state) {
735 case ODEBUG_STATE_ACTIVE:
736 case ODEBUG_STATE_NOTAVAILABLE:
737 if (debug_object_fixup(fixup: descr->fixup_activate, addr, state: o.state))
738 return 0;
739 fallthrough;
740 default:
741 return -EINVAL;
742 }
743}
744EXPORT_SYMBOL_GPL(debug_object_activate);
745
746/**
747 * debug_object_deactivate - debug checks when an object is deactivated
748 * @addr: address of the object
749 * @descr: pointer to an object specific debug description structure
750 */
751void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
752{
753 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
754 struct debug_bucket *db;
755 struct debug_obj *obj;
756 unsigned long flags;
757
758 if (!debug_objects_enabled)
759 return;
760
761 db = get_bucket(addr: (unsigned long) addr);
762
763 raw_spin_lock_irqsave(&db->lock, flags);
764
765 obj = lookup_object(addr, b: db);
766 if (obj) {
767 switch (obj->state) {
768 case ODEBUG_STATE_DESTROYED:
769 break;
770 case ODEBUG_STATE_INIT:
771 case ODEBUG_STATE_INACTIVE:
772 case ODEBUG_STATE_ACTIVE:
773 if (obj->astate)
774 break;
775 obj->state = ODEBUG_STATE_INACTIVE;
776 fallthrough;
777 default:
778 raw_spin_unlock_irqrestore(&db->lock, flags);
779 return;
780 }
781 o = *obj;
782 }
783
784 raw_spin_unlock_irqrestore(&db->lock, flags);
785 debug_print_object(obj: &o, msg: "deactivate");
786}
787EXPORT_SYMBOL_GPL(debug_object_deactivate);
788
789/**
790 * debug_object_destroy - debug checks when an object is destroyed
791 * @addr: address of the object
792 * @descr: pointer to an object specific debug description structure
793 */
794void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
795{
796 struct debug_obj *obj, o;
797 struct debug_bucket *db;
798 unsigned long flags;
799
800 if (!debug_objects_enabled)
801 return;
802
803 db = get_bucket(addr: (unsigned long) addr);
804
805 raw_spin_lock_irqsave(&db->lock, flags);
806
807 obj = lookup_object(addr, b: db);
808 if (!obj) {
809 raw_spin_unlock_irqrestore(&db->lock, flags);
810 return;
811 }
812
813 switch (obj->state) {
814 case ODEBUG_STATE_ACTIVE:
815 case ODEBUG_STATE_DESTROYED:
816 break;
817 case ODEBUG_STATE_NONE:
818 case ODEBUG_STATE_INIT:
819 case ODEBUG_STATE_INACTIVE:
820 obj->state = ODEBUG_STATE_DESTROYED;
821 fallthrough;
822 default:
823 raw_spin_unlock_irqrestore(&db->lock, flags);
824 return;
825 }
826
827 o = *obj;
828 raw_spin_unlock_irqrestore(&db->lock, flags);
829 debug_print_object(obj: &o, msg: "destroy");
830
831 if (o.state == ODEBUG_STATE_ACTIVE)
832 debug_object_fixup(fixup: descr->fixup_destroy, addr, state: o.state);
833}
834EXPORT_SYMBOL_GPL(debug_object_destroy);
835
836/**
837 * debug_object_free - debug checks when an object is freed
838 * @addr: address of the object
839 * @descr: pointer to an object specific debug description structure
840 */
841void debug_object_free(void *addr, const struct debug_obj_descr *descr)
842{
843 struct debug_obj *obj, o;
844 struct debug_bucket *db;
845 unsigned long flags;
846
847 if (!debug_objects_enabled)
848 return;
849
850 db = get_bucket(addr: (unsigned long) addr);
851
852 raw_spin_lock_irqsave(&db->lock, flags);
853
854 obj = lookup_object(addr, b: db);
855 if (!obj) {
856 raw_spin_unlock_irqrestore(&db->lock, flags);
857 return;
858 }
859
860 switch (obj->state) {
861 case ODEBUG_STATE_ACTIVE:
862 break;
863 default:
864 hlist_del(n: &obj->node);
865 raw_spin_unlock_irqrestore(&db->lock, flags);
866 free_object(obj);
867 return;
868 }
869
870 o = *obj;
871 raw_spin_unlock_irqrestore(&db->lock, flags);
872 debug_print_object(obj: &o, msg: "free");
873
874 debug_object_fixup(fixup: descr->fixup_free, addr, state: o.state);
875}
876EXPORT_SYMBOL_GPL(debug_object_free);
877
878/**
879 * debug_object_assert_init - debug checks when object should be init-ed
880 * @addr: address of the object
881 * @descr: pointer to an object specific debug description structure
882 */
883void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
884{
885 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
886 struct debug_bucket *db;
887 struct debug_obj *obj;
888 unsigned long flags;
889
890 if (!debug_objects_enabled)
891 return;
892
893 debug_objects_fill_pool();
894
895 db = get_bucket(addr: (unsigned long) addr);
896
897 raw_spin_lock_irqsave(&db->lock, flags);
898 obj = lookup_object_or_alloc(addr, b: db, descr, onstack: false, alloc_ifstatic: true);
899 raw_spin_unlock_irqrestore(&db->lock, flags);
900 if (likely(!IS_ERR_OR_NULL(obj)))
901 return;
902
903 /* If NULL the allocation has hit OOM */
904 if (!obj) {
905 debug_objects_oom();
906 return;
907 }
908
909 /* Object is neither tracked nor static. It's not initialized. */
910 debug_print_object(obj: &o, msg: "assert_init");
911 debug_object_fixup(fixup: descr->fixup_assert_init, addr, state: ODEBUG_STATE_NOTAVAILABLE);
912}
913EXPORT_SYMBOL_GPL(debug_object_assert_init);
914
915/**
916 * debug_object_active_state - debug checks object usage state machine
917 * @addr: address of the object
918 * @descr: pointer to an object specific debug description structure
919 * @expect: expected state
920 * @next: state to move to if expected state is found
921 */
922void
923debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
924 unsigned int expect, unsigned int next)
925{
926 struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
927 struct debug_bucket *db;
928 struct debug_obj *obj;
929 unsigned long flags;
930
931 if (!debug_objects_enabled)
932 return;
933
934 db = get_bucket(addr: (unsigned long) addr);
935
936 raw_spin_lock_irqsave(&db->lock, flags);
937
938 obj = lookup_object(addr, b: db);
939 if (obj) {
940 switch (obj->state) {
941 case ODEBUG_STATE_ACTIVE:
942 if (obj->astate != expect)
943 break;
944 obj->astate = next;
945 raw_spin_unlock_irqrestore(&db->lock, flags);
946 return;
947 default:
948 break;
949 }
950 o = *obj;
951 }
952
953 raw_spin_unlock_irqrestore(&db->lock, flags);
954 debug_print_object(obj: &o, msg: "active_state");
955}
956EXPORT_SYMBOL_GPL(debug_object_active_state);
957
958#ifdef CONFIG_DEBUG_OBJECTS_FREE
959static void __debug_check_no_obj_freed(const void *address, unsigned long size)
960{
961 unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
962 int cnt, objs_checked = 0;
963 struct debug_obj *obj, o;
964 struct debug_bucket *db;
965 struct hlist_node *tmp;
966
967 saddr = (unsigned long) address;
968 eaddr = saddr + size;
969 paddr = saddr & ODEBUG_CHUNK_MASK;
970 chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
971 chunks >>= ODEBUG_CHUNK_SHIFT;
972
973 for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
974 db = get_bucket(addr: paddr);
975
976repeat:
977 cnt = 0;
978 raw_spin_lock_irqsave(&db->lock, flags);
979 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
980 cnt++;
981 oaddr = (unsigned long) obj->object;
982 if (oaddr < saddr || oaddr >= eaddr)
983 continue;
984
985 switch (obj->state) {
986 case ODEBUG_STATE_ACTIVE:
987 o = *obj;
988 raw_spin_unlock_irqrestore(&db->lock, flags);
989 debug_print_object(obj: &o, msg: "free");
990 debug_object_fixup(fixup: o.descr->fixup_free, addr: (void *)oaddr, state: o.state);
991 goto repeat;
992 default:
993 hlist_del(n: &obj->node);
994 __free_object(obj);
995 break;
996 }
997 }
998 raw_spin_unlock_irqrestore(&db->lock, flags);
999
1000 if (cnt > debug_objects_maxchain)
1001 debug_objects_maxchain = cnt;
1002
1003 objs_checked += cnt;
1004 }
1005
1006 if (objs_checked > debug_objects_maxchecked)
1007 debug_objects_maxchecked = objs_checked;
1008
1009 /* Schedule work to actually kmem_cache_free() objects */
1010 if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1011 WRITE_ONCE(obj_freeing, true);
1012 schedule_delayed_work(dwork: &debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1013 }
1014}
1015
1016void debug_check_no_obj_freed(const void *address, unsigned long size)
1017{
1018 if (debug_objects_enabled)
1019 __debug_check_no_obj_freed(address, size);
1020}
1021#endif
1022
1023#ifdef CONFIG_DEBUG_FS
1024
1025static int debug_stats_show(struct seq_file *m, void *v)
1026{
1027 int cpu, obj_percpu_free = 0;
1028
1029 for_each_possible_cpu(cpu)
1030 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1031
1032 seq_printf(m, fmt: "max_chain :%d\n", debug_objects_maxchain);
1033 seq_printf(m, fmt: "max_checked :%d\n", debug_objects_maxchecked);
1034 seq_printf(m, fmt: "warnings :%d\n", debug_objects_warnings);
1035 seq_printf(m, fmt: "fixups :%d\n", debug_objects_fixups);
1036 seq_printf(m, fmt: "pool_free :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1037 seq_printf(m, fmt: "pool_pcp_free :%d\n", obj_percpu_free);
1038 seq_printf(m, fmt: "pool_min_free :%d\n", obj_pool_min_free);
1039 seq_printf(m, fmt: "pool_used :%d\n", obj_pool_used - obj_percpu_free);
1040 seq_printf(m, fmt: "pool_max_used :%d\n", obj_pool_max_used);
1041 seq_printf(m, fmt: "on_free_list :%d\n", READ_ONCE(obj_nr_tofree));
1042 seq_printf(m, fmt: "objs_allocated:%d\n", debug_objects_allocated);
1043 seq_printf(m, fmt: "objs_freed :%d\n", debug_objects_freed);
1044 return 0;
1045}
1046DEFINE_SHOW_ATTRIBUTE(debug_stats);
1047
1048static int __init debug_objects_init_debugfs(void)
1049{
1050 struct dentry *dbgdir;
1051
1052 if (!debug_objects_enabled)
1053 return 0;
1054
1055 dbgdir = debugfs_create_dir(name: "debug_objects", NULL);
1056
1057 debugfs_create_file(name: "stats", mode: 0444, parent: dbgdir, NULL, fops: &debug_stats_fops);
1058
1059 return 0;
1060}
1061__initcall(debug_objects_init_debugfs);
1062
1063#else
1064static inline void debug_objects_init_debugfs(void) { }
1065#endif
1066
1067#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1068
1069/* Random data structure for the self test */
1070struct self_test {
1071 unsigned long dummy1[6];
1072 int static_init;
1073 unsigned long dummy2[3];
1074};
1075
1076static __initconst const struct debug_obj_descr descr_type_test;
1077
1078static bool __init is_static_object(void *addr)
1079{
1080 struct self_test *obj = addr;
1081
1082 return obj->static_init;
1083}
1084
1085/*
1086 * fixup_init is called when:
1087 * - an active object is initialized
1088 */
1089static bool __init fixup_init(void *addr, enum debug_obj_state state)
1090{
1091 struct self_test *obj = addr;
1092
1093 switch (state) {
1094 case ODEBUG_STATE_ACTIVE:
1095 debug_object_deactivate(obj, &descr_type_test);
1096 debug_object_init(obj, &descr_type_test);
1097 return true;
1098 default:
1099 return false;
1100 }
1101}
1102
1103/*
1104 * fixup_activate is called when:
1105 * - an active object is activated
1106 * - an unknown non-static object is activated
1107 */
1108static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1109{
1110 struct self_test *obj = addr;
1111
1112 switch (state) {
1113 case ODEBUG_STATE_NOTAVAILABLE:
1114 return true;
1115 case ODEBUG_STATE_ACTIVE:
1116 debug_object_deactivate(obj, &descr_type_test);
1117 debug_object_activate(obj, &descr_type_test);
1118 return true;
1119
1120 default:
1121 return false;
1122 }
1123}
1124
1125/*
1126 * fixup_destroy is called when:
1127 * - an active object is destroyed
1128 */
1129static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1130{
1131 struct self_test *obj = addr;
1132
1133 switch (state) {
1134 case ODEBUG_STATE_ACTIVE:
1135 debug_object_deactivate(obj, &descr_type_test);
1136 debug_object_destroy(obj, &descr_type_test);
1137 return true;
1138 default:
1139 return false;
1140 }
1141}
1142
1143/*
1144 * fixup_free is called when:
1145 * - an active object is freed
1146 */
1147static bool __init fixup_free(void *addr, enum debug_obj_state state)
1148{
1149 struct self_test *obj = addr;
1150
1151 switch (state) {
1152 case ODEBUG_STATE_ACTIVE:
1153 debug_object_deactivate(obj, &descr_type_test);
1154 debug_object_free(obj, &descr_type_test);
1155 return true;
1156 default:
1157 return false;
1158 }
1159}
1160
1161static int __init
1162check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1163{
1164 struct debug_bucket *db;
1165 struct debug_obj *obj;
1166 unsigned long flags;
1167 int res = -EINVAL;
1168
1169 db = get_bucket(addr: (unsigned long) addr);
1170
1171 raw_spin_lock_irqsave(&db->lock, flags);
1172
1173 obj = lookup_object(addr, b: db);
1174 if (!obj && state != ODEBUG_STATE_NONE) {
1175 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1176 goto out;
1177 }
1178 if (obj && obj->state != state) {
1179 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1180 obj->state, state);
1181 goto out;
1182 }
1183 if (fixups != debug_objects_fixups) {
1184 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1185 fixups, debug_objects_fixups);
1186 goto out;
1187 }
1188 if (warnings != debug_objects_warnings) {
1189 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1190 warnings, debug_objects_warnings);
1191 goto out;
1192 }
1193 res = 0;
1194out:
1195 raw_spin_unlock_irqrestore(&db->lock, flags);
1196 if (res)
1197 debug_objects_enabled = 0;
1198 return res;
1199}
1200
1201static __initconst const struct debug_obj_descr descr_type_test = {
1202 .name = "selftest",
1203 .is_static_object = is_static_object,
1204 .fixup_init = fixup_init,
1205 .fixup_activate = fixup_activate,
1206 .fixup_destroy = fixup_destroy,
1207 .fixup_free = fixup_free,
1208};
1209
1210static __initdata struct self_test obj = { .static_init = 0 };
1211
1212static void __init debug_objects_selftest(void)
1213{
1214 int fixups, oldfixups, warnings, oldwarnings;
1215 unsigned long flags;
1216
1217 local_irq_save(flags);
1218
1219 fixups = oldfixups = debug_objects_fixups;
1220 warnings = oldwarnings = debug_objects_warnings;
1221 descr_test = &descr_type_test;
1222
1223 debug_object_init(&obj, &descr_type_test);
1224 if (check_results(addr: &obj, state: ODEBUG_STATE_INIT, fixups, warnings))
1225 goto out;
1226 debug_object_activate(&obj, &descr_type_test);
1227 if (check_results(addr: &obj, state: ODEBUG_STATE_ACTIVE, fixups, warnings))
1228 goto out;
1229 debug_object_activate(&obj, &descr_type_test);
1230 if (check_results(addr: &obj, state: ODEBUG_STATE_ACTIVE, fixups: ++fixups, warnings: ++warnings))
1231 goto out;
1232 debug_object_deactivate(&obj, &descr_type_test);
1233 if (check_results(addr: &obj, state: ODEBUG_STATE_INACTIVE, fixups, warnings))
1234 goto out;
1235 debug_object_destroy(&obj, &descr_type_test);
1236 if (check_results(addr: &obj, state: ODEBUG_STATE_DESTROYED, fixups, warnings))
1237 goto out;
1238 debug_object_init(&obj, &descr_type_test);
1239 if (check_results(addr: &obj, state: ODEBUG_STATE_DESTROYED, fixups, warnings: ++warnings))
1240 goto out;
1241 debug_object_activate(&obj, &descr_type_test);
1242 if (check_results(addr: &obj, state: ODEBUG_STATE_DESTROYED, fixups, warnings: ++warnings))
1243 goto out;
1244 debug_object_deactivate(&obj, &descr_type_test);
1245 if (check_results(addr: &obj, state: ODEBUG_STATE_DESTROYED, fixups, warnings: ++warnings))
1246 goto out;
1247 debug_object_free(&obj, &descr_type_test);
1248 if (check_results(addr: &obj, state: ODEBUG_STATE_NONE, fixups, warnings))
1249 goto out;
1250
1251 obj.static_init = 1;
1252 debug_object_activate(&obj, &descr_type_test);
1253 if (check_results(addr: &obj, state: ODEBUG_STATE_ACTIVE, fixups, warnings))
1254 goto out;
1255 debug_object_init(&obj, &descr_type_test);
1256 if (check_results(addr: &obj, state: ODEBUG_STATE_INIT, fixups: ++fixups, warnings: ++warnings))
1257 goto out;
1258 debug_object_free(&obj, &descr_type_test);
1259 if (check_results(addr: &obj, state: ODEBUG_STATE_NONE, fixups, warnings))
1260 goto out;
1261
1262#ifdef CONFIG_DEBUG_OBJECTS_FREE
1263 debug_object_init(&obj, &descr_type_test);
1264 if (check_results(addr: &obj, state: ODEBUG_STATE_INIT, fixups, warnings))
1265 goto out;
1266 debug_object_activate(&obj, &descr_type_test);
1267 if (check_results(addr: &obj, state: ODEBUG_STATE_ACTIVE, fixups, warnings))
1268 goto out;
1269 __debug_check_no_obj_freed(address: &obj, size: sizeof(obj));
1270 if (check_results(addr: &obj, state: ODEBUG_STATE_NONE, fixups: ++fixups, warnings: ++warnings))
1271 goto out;
1272#endif
1273 pr_info("selftest passed\n");
1274
1275out:
1276 debug_objects_fixups = oldfixups;
1277 debug_objects_warnings = oldwarnings;
1278 descr_test = NULL;
1279
1280 local_irq_restore(flags);
1281}
1282#else
1283static inline void debug_objects_selftest(void) { }
1284#endif
1285
1286/*
1287 * Called during early boot to initialize the hash buckets and link
1288 * the static object pool objects into the poll list. After this call
1289 * the object tracker is fully operational.
1290 */
1291void __init debug_objects_early_init(void)
1292{
1293 int i;
1294
1295 for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1296 raw_spin_lock_init(&obj_hash[i].lock);
1297
1298 for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1299 hlist_add_head(n: &obj_static_pool[i].node, h: &obj_pool);
1300}
1301
1302/*
1303 * Convert the statically allocated objects to dynamic ones:
1304 */
1305static int __init debug_objects_replace_static_objects(void)
1306{
1307 struct debug_bucket *db = obj_hash;
1308 struct hlist_node *tmp;
1309 struct debug_obj *obj, *new;
1310 HLIST_HEAD(objects);
1311 int i, cnt = 0;
1312
1313 for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1314 obj = kmem_cache_zalloc(k: obj_cache, GFP_KERNEL);
1315 if (!obj)
1316 goto free;
1317 hlist_add_head(n: &obj->node, h: &objects);
1318 }
1319
1320 debug_objects_allocated += i;
1321
1322 /*
1323 * debug_objects_mem_init() is now called early that only one CPU is up
1324 * and interrupts have been disabled, so it is safe to replace the
1325 * active object references.
1326 */
1327
1328 /* Remove the statically allocated objects from the pool */
1329 hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1330 hlist_del(n: &obj->node);
1331 /* Move the allocated objects to the pool */
1332 hlist_move_list(old: &objects, new: &obj_pool);
1333
1334 /* Replace the active object references */
1335 for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1336 hlist_move_list(old: &db->list, new: &objects);
1337
1338 hlist_for_each_entry(obj, &objects, node) {
1339 new = hlist_entry(obj_pool.first, typeof(*obj), node);
1340 hlist_del(n: &new->node);
1341 /* copy object data */
1342 *new = *obj;
1343 hlist_add_head(n: &new->node, h: &db->list);
1344 cnt++;
1345 }
1346 }
1347
1348 pr_debug("%d of %d active objects replaced\n",
1349 cnt, obj_pool_used);
1350 return 0;
1351free:
1352 hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1353 hlist_del(n: &obj->node);
1354 kmem_cache_free(s: obj_cache, objp: obj);
1355 }
1356 return -ENOMEM;
1357}
1358
1359/*
1360 * Called after the kmem_caches are functional to setup a dedicated
1361 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1362 * prevents that the debug code is called on kmem_cache_free() for the
1363 * debug tracker objects to avoid recursive calls.
1364 */
1365void __init debug_objects_mem_init(void)
1366{
1367 int cpu, extras;
1368
1369 if (!debug_objects_enabled)
1370 return;
1371
1372 /*
1373 * Initialize the percpu object pools
1374 *
1375 * Initialization is not strictly necessary, but was done for
1376 * completeness.
1377 */
1378 for_each_possible_cpu(cpu)
1379 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1380
1381 obj_cache = kmem_cache_create(name: "debug_objects_cache",
1382 size: sizeof (struct debug_obj), align: 0,
1383 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1384 NULL);
1385
1386 if (!obj_cache || debug_objects_replace_static_objects()) {
1387 debug_objects_enabled = 0;
1388 kmem_cache_destroy(s: obj_cache);
1389 pr_warn("out of memory.\n");
1390 return;
1391 } else
1392 debug_objects_selftest();
1393
1394#ifdef CONFIG_HOTPLUG_CPU
1395 cpuhp_setup_state_nocalls(state: CPUHP_DEBUG_OBJ_DEAD, name: "object:offline", NULL,
1396 teardown: object_cpu_offline);
1397#endif
1398
1399 /*
1400 * Increase the thresholds for allocating and freeing objects
1401 * according to the number of possible CPUs available in the system.
1402 */
1403 extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1404 debug_objects_pool_size += extras;
1405 debug_objects_pool_min_level += extras;
1406}
1407

Provided by KDAB

Privacy Policy
Improve your Profiling and Debugging skills
Find out more

source code of linux/lib/debugobjects.c